Pneumatic concrete conveying and placing



Feb. 7, 1928'.

J. H. FITZGERALD PNEUMATIC CONCRETE CONVEYING AND PLACING Filed Dec. 9, 19 24 2 Sheets-Sheet 1 I v avwemto'z 351 abtom'ttt Feb. 7, 1928f J. H. FITZGERALD PNEUMATIC CONCRETE CONVEYING AND PLACING 2 Sheets-Sheet 2 Filed Dec. 9, 1924 Qimngntoz Gum/n44, D

Patented Feb. 7, 19 28.

/ UNI'I'ED STATES NEW JERSEY.

1,658,046 PATENT OFFICE.

PNEUMATIC CONCRETE R vme AND PLAGEIG.

Application filed December 9, 1924. Serial No. 754.717.

\ The present improvements relate to method and apparatus for placing concreteand the like by means of compressed air,

while in a wet or more or less fluent condition immediately after mixing. The improvements are also of such a nature that mixing of the concrete aggregates as well as placing may be accomplished thereby. In

the lining of tunnels, and in other places where it is difiicult to place concrete by gravity or by hand, an immense saving is accomplished, and better results obtalned by the employment of compressed air to convey the concrete to the point of placement and place it in the form. Such pneumatic conveyance and placement when properly practiced is convenient, safe and speedy, effects a great saving in cost and results in a much better lining or other structure. This has been demonstrated by many years of experience.

Numerous patents have been issued for 1mprovements in methods and apparatusfor carrying on this work, and some of them have proved very eflicieut. Difliculty has been experienced, however, under certain conditions of operation, and one of the conditions which.

makes pneumatic operation diflicult is the necessity for working in a tunnel or other excavation where there is not suflicient head room to permit the employment of gravity in the placing apparatus. In such cases what is known as horizontalapparatus, or apparatus in which the materials move'to the discharge outlet in a substantially hori- 85 zontal instead of a vertical direction, has been employed. Various difiiculties in such apparatus however, have been experienced due to the fact that the heavy non-cohesive mass of mixed concrete aggregates must be 0 propelled toward the discharge opening by mechanical means, and such means are not easily or economically operated in such an environment. Thus, a pneumatically operated plunger has been employed to move the aggregates from the charging point to'the discharge outlet, but such which means a large expenditure of and isnot as thorough in its work or as dependable as it should be. Other devices have been employed with equally tory results. Y i

It is the primary object of the present implunger consumes a relatively large volume of compressed air,

screw conveyor with a suitab provements to overcome the difliculties of moving and discharging the materials in a 5 horizontal pneumatic placing apparatus, and

to provide for a better mixing and placin thereof and the maintenance of the concrete in a thoroughly mixed state from the pneumatic placing apparatus to the point of application.

The improvements are illustrated in the accompanying drawings, in which Figure 1 is a longitudinal vertical section taken medially of a pneumatic concrete placing apparatus embodying the improvements; and

Figure 2 is a view of the discharge end thereof, with a part of the outer shell or casing broken away to expose-interior parts.

In the illustrative apparatus for the embodiment and practice of the present improvements shown in the drawings the vessel or retort in which the concrete aggregates are received, and from which they are .discharged pneumatically, comprises a cylinder 1 with front and rear heads 2 and 3, and having a charging opening 4 at its top near the rear end and a discharging opening 23 at the bottom 5 and at its forward end. The

charging opening is provided with a door 6 mounted to swing inwardly and downwardly and is operated by a lever 7 ivoted at 8,- a link 9 connecting the door with the lever and a hand lever 10 connected with the lever 7 by link 11. A suitable annular seat 12 is provided for the sealing of the door, and 1t is held in closed position by the short arm 13 fixed to the hand lever 10 in such position that it is on dead center behind its pivot 14 when the door is closed. A pi 15 with a valve 16 communicates with t e forward head of the vessel, and from this pipe a small branch pipe 17?, to which a pressure ge ma connected, extends. This pipe lll may b: used for the purpose of washing out the apparatus, or to inject air or' waterthereinto during the operation. thereo if desired.

Mounted in'suitable bearings 18 and 19 in the heads of the retort is a shaft 20 hearing .a Worm or screw conveyor 21,.and the end of in.

this shaft which extends through the head 3 has a ar 22 keyed thereon. This gear is provid for the purpose of connecting the I 1e source of I power whereby it may be rotated. As the particular character of the power employed however, should be under is not of the greatest importance, it is not illustrated in detail. The power supplied, absolute control, so that the speed of the conveyor can be regulated and adjusted to meet variations in the nature of the material acted u and pressure of the compre and other conditions. An electric motor geared down to a relatively slow speed has been found most satisfactory, but the power air employed may be furnished by air or other fluid under supplied by the pipe and passed theother parts of the 'apparatus pressure. The screw conveyor rotates clockwise-as viewed from the discharge end of the vessel-as indicated by the arrow, and propels the concrete, which is dumped Into the'vessel through the chargin opening m a batch or charge, "to the disc arge 'opemng and not only conveys it and feeds it to said opening at a regular rate and in a manner best calculated to secure "its proper conveyance and placement, but breaks up the batch or charge and mixes it to a certain extent. 'Should the discharge opening become clogged in any manner it is possible to reverse the rotation of the screw and thus clear the open- The discharge opening 23 is located at the bottom of the vessel at its forward end and. permits the'material to fall into the box where it is taken up by thecompressed air into the conduit 26 through which it is conveyed to the point of placement. The supply of comressed air-through the pipe 25 is'controlled by a valve 27, and should be-regulated to do its work properly and give the most desired results. The regulation of the supply of anand the relative speed of the screw conveyor are matters to be determined by the conditions of use which vary to a considerable extent. The supply of air, however, should be at a highrate of speed, and the speed of the conveyor should be such as to give the air a sufiicientload to carry without danger of causing clogging. Under normal conditions the-conduit 26 is open at both ends, so that the air and the concrete conveyed thereby will be permitted to pass therethrough f ly and at a considerable rate of speed... If,

however, the conditions make it advisable the conduit may be provided with a reducing nozzle or a valve or reducer intermediate its ends. q 1

A suitable housing 28 for-the gear'22 and the power device is provided, and this, and

are mounted one. base 29. p

In operation a batch or charge of concrete is dumped into the vessel through the charging opening 4 and the opening closed; the' compressed air valve is then opened and air under pressure permitted to pass through the discharge chamber or box 24 into the retort and through the conveying conduit 26. The screw is then started and operated n, the speed bottom, whic constructed to at a rate of speed calculated to give the results and the adjustment of the conveyor s and the air supplied ma be made by 0m ing the manner in whicli the material is discharged from the conduit 26.

The discharge and conveyance of the ma-- terial is caused by the nozzle action of the air issuing from the. mouth of the pipe 25, and passing through the box 24 and conduit 26 and by a certain pressure differential pro.- duced thereby, aided by the screw conveyor. At the same time the material is not broken or disintegrated by the air but is conveyed and delivered to the point of placing in a comparatively solid column or stream, and this is due largely to the fact that it is pomible' to regulate the feeding of the material to the discharge conduit so that it will The power device indicated comprises amotor 30 governed by a controller 33 through conductor 31,

a gear 32 in mesh with the gear 22 on the end of the worm shaft 20, a shaft 34 on which the gear 32 is keyed and a large'gear 35 kc ed to the other end of the shaft and in mes with the pinion 36 onthe endof the motor shaft. p The discharge chamber 24 is substantially U-shaped in cross section, and its open top is approximately the same size as the discharge opening 23. It tapers toward the ameter and shape as the conduit 26. This provides. for the free movement of the ma-- terial into the discharge, and tends to prevent the said material from spreading and being disintegrated by the blast'of air from the pipe 25. It also ensures a suflicient supply of material to give the air a suflicient load and thus reduce the danger of blowing and other undesirable results.

What I claim is:

1. In an apparatus for discharging and placing concrete and the like pneumatically,

an air-tight .vemel adapted to receive and hold the material in a mass, said vesselhavmg a dlscharge opening at its lower part and being of greater length zontally disposed, "a conveyor positioned within the lower confines of said vessel and spaced from the walls'thereof arran to convey the material from one end t ereof towards the discharge opening and bein capable of regulation to different sp a discharge conduit in communication. with said opening intheyessel and means for supplying comp air to said conduit and to said vessel and a pipe of relatively small diameter, said pipe dircctairin line with the dischar conduit, said conveyor and discharge opening being exposed to the pressure main: tamed in the vessel, andmeansfor regulate maintaining the same there-- in and in the discharge opening including.

is substantially the same dithan depth and horii 20 convey the material from one end 0 said an air-tight vessel adapted ing a discharge emon ing the volume and speed of the air dischar ed from said pipe.

2. e combination of elements s ified in claim 1, the conveying means in t e vessel' comprising a vscrew conveyor .in the bot-v vessel towardthe discharge opening and being ca able of regulation to difierent speeds,

'a disc arge chamber communicating with said discharge opening, a discharge conduit in communication with said chamber,

small diameter having a pipe of relativel adjacent-said discharge an outlet positione opening for suppl conduit and to sai vessel through said chamber and discharge opening, said i positioned to direct air into said con wt, and means for re lating the volume and .s of the air discharged from said pipe,

yin compressed air to said t e said conveyor and outlet being constructed and arrangedto be subject at alltimes to direct air pressure from the upper part of the vesel,

Witness my hand this 4th day of December, '1924, at the city of New York,-

county of New York, State of New York.

JAMES H. FITZGERALD. 

